Ch - 14 (Metals and Alloys)
No description yet. This curated deck is ready for daily study.
Card preview (21)
What can the periodic table be divided into?
Metals and Non - metals
What is it called if they display properties of both metal and non-metals?
Metalloids or semi metals
What are the properties of metals?
• conduct heat and electricity • malleable (hammered and made into different shapes) • ductile (can be drawn into wires) • Lustrous • High density • High m.p. • Positive ion through electron loss • Basic oxides
What are the properties of non-metals?
• Do not conduct heat and electricity • Brittle • dull n non-reflective • Low density • low m.p.(mostly gases) • negative ion cuz they gain electron(except H) • Acidic oxides
How can the chemical properties of metals be studied?
By analysing their reactions with: - Water - Dilute acid - Oxygen
What happens when metal reacts with cold water?
Metal + Water –> Metal hydroxide + Hydrogen
What about metals that react with steam?
Metal + Steam –> Metal oxide + Hydrogen
What happens when metal reacts with acids?
• Hydrogen atom in the acid is replaced by metal atom
What is the equation when metal reacts with acids?
Metal + Acid –> Salt + Hydrogen
What are the uses of aluminium?
• Aeroplane body (High strength to weight ratio, low density) • overhead power cables (good conductor of electricity) • Saucepans (Good conductor of heat) • Food cans ( Non-toxic, resistant to corrosion and acidic food stuff) • Window frames (Resistant to corrosion)
What are the uses of copper?
-Electrical wires (Good conductor of electricity and malleable) • Water pipes (Ductile, and doesn’t react with H2O)
What is an alloy?
Alloy is a mixture of two or more metals and non-metals such as carbon
What type of properties do alloys have?
• Different from metals • More strength • Hardness • resistant to corrosion • extreme temp • More useful than pure metals
What are some common alloys?
• Brass (copper and zinc) • Stainless steel (mixture of iron, carbon, chromium and nickel)
What is the use of brass?
• Stronger than either metal • Musical instruments • ornaments • door knobs
What is the use of stainless steel?
• ## cutlery (cuz hardness and resistance to corrosion)
What is the use of the alloys of iron and tungsten?
• Hard • Resistant to High temp.
What is a property of an alloy of iron mixed with chromium and nickel?
Resistant to corrosion
What is the use of aluminium mixed with copper, manganese and silicon?
• Aircraft body (strong alloy) • low density
Why is the arrangement of alloys different than of metals?
• Different sized atoms • Distorts the regular arrangement of atoms
Why are alloys much harder than pure metals?
• Different sized atoms • Harder for layers to slide over each other.